The swift decline of the Australian dollar is causing investors to reconsider how they position their portfolios as the surging greenback wreaks havoc across financial markets.

The local currency hit a fresh 2½-year low of US61.69¢ last week, with BetaShares warning on Monday that it could fall to US58¢ in the next three to six months. Meanwhile, the US Dollar Index sits around 112.11, just shy of the 20-year high of 114.78 it touched late last month.